Objective : It has been thought that estrogen has neuroleptic like effect in women schizophrenic patients. This study aimed to investigate neuroleptic side-effects severity in women with schizophrenia and to investigate their putative association with variations in sex steroids over menstrual cycle. Based on the estrogen theory, The author hypothesized that parkinsonian side-effects would be exacerbated when estrogen levels were high. Method : 26 schizophrenic women were assessed using the ESRS(Extrapyramidal Symptom Rating Scale) and estrogen analysis. Tests were conducted twice, in the mid luteal and mid follicular phase. Result : It was hypothesized that high level of estrogen would lead to an exacerbation of parkinsonian side-effects but the results indicated that parkinsonian side effects decreased overall when estrogen levels were high. This effects were more marked for the group taking typical neuroleptics than those taking atypical neuroleptics. Conclusion : The results of this study suggest that estrogen and progesteron may reduce the severity of neuroleptic induced extrapyramidal side effects over menstrual cycle in women with schizophrenia. It was concluded that estrogen has different effects on dopamine dynamics in the mesolimbic and mesostriatal pathways according to estrogen, progesteron, catecol estrogen, prolactine.